Mineral oil compositions



UNITED STATES PATENT OFFICE MINERAL OIL COMPOSITIONS Stanley P. Waugh,Westiield, N. 1., designer to Tide Water Associated Oil Company, Bayo N.1., a corporation of Delaware No Drawing. Application June 26, 1947,Serial No. 757,325

7 Claims. (Cl. 25%) The present invention relates to improved mineraloil compositions, and, more particularly, to mineral oil compositionshaving improved performance characteristics. Although the novelcompositions, as embodied herein, flnd utility for many usages, they areparticularly adapted for use as lubricants, and especially forlubricating of engines operated under wet conditions, as for example,the wick-feed type of reciprocating marine engines. Hence, for purposesof illustration, the description of my invention, as is set forthhereinafter, is described in its adaptability to mineral oilcompositions especially suitable for use in lubricating of marineengines of the foregoing type.

It is well-known to those skilled in the art that lubricatingcompositions for marine engines, e. g., wick-feed type reciprocatingengines, should desirably possess certain essential characteristics foroptimum performance. In particular, such compositions should not onlypossess certain physical characteristics, including viscosity, pourpoint, and the like, of desired values, but should wick-feedsatisfactorily, readily emulsify with water (such as condensate formedduring operation of the engine) and aqueous salt solutions, and inemulsified form, should possess good adhering characteristics to metalsurfaces. For most purposes, mineral oils or fractions'thereof do notpossess all of the aforedescribed desired characteristics, and hence, itis common practice, in providing suitable mineral oil base compositionsfor such usage, to blend mineral oils with bodied fatty oils. Ingeneral, compositions now in wide use commercially comprise a suitablemineral oil base stock having dissolved therein a substantial amount ofa blown fatty oil, e. g., from about to 20%, and for the most part, atleast about 15% by weight of the blown fatty oil. Use of blown fattyoils in such substantial proportional amounts has been found necessaryfor modification of suitable mineral oil base stocks to providecompounded compositions having the aforedescribed desired properties.More specifically, suitable examples of such lubricating compositionsare the compounded mineral oils meeting the specification requirementsof Bureau of Ships, Pamphlet N. B. S. 431, Oil, Lubricating Engines(Marine), compounded Navy Symbol 4065, relating to compositions having aviscosity (Saybolt) of 65-80 seconds at 210 F., a pour point not above35 F., and suitable for lubrication of marine engines (wick-feed) andbearings and thrust bearings of auxiliary deck machinery. In brief, acomposition meeting the foregoing speci- -2 flcation comprises asuitable mineral oil base stock having dissolved therein about 15-20% byweight of a suitable bodied fatty oil, e. g., blown rapeseed oil.

Although substantially high proportional amounts of blown fatty oilshave been found necessary to desirably modify mineral oil base stocksfor satisfactory performance thereof in marine engine lubrication, useof such large proportional amounts of blown fatty oils often impartcertain objectional characteristics to the compounded composition. Forexample, blown fatty oils tend to decompose at elevated temperatureswith production of charred or gummy materials and hence, deleteriouslyaffect performance of the compounded composition at elevatedtemperatures; furthermore, blown fatty oils generally contain aconsiderable amount of free fatty acids, which tend to enhance corrosionof metal parts in contact with the composition, and additionally,depending upon the degree to which the blown fatty oils have beenoxidized and/or polymerized, they tend to form oil-insoluble materials,probably due to continuing oxidation and/or polymerization of the bodiedoils. It is highly desirable, therefore, apart from economic reasons, toemploy bodied fatty oils in the minimum amount required to modify themineral'oil base stock and provide blended compositions having theaforedescribed desired characteristics. As described hereinbefore;substantial amounts of bodied fatty oils, e. g., at least about 15% byweight, are generally employed so as to desirably modify the mineral oilbase stocks, and by use of such large proportional amounts, thecompounded compositions usually possess the hereinbefore describedobjectionable features resulting from' the use of high concentrations ofbodied fatty oils in the compositions.

The present invention is based on the discovery that by incorporatingcertain substances, as described more fully hereinafter, into a suitablemineral oil base stock, the concentration of blown fatty oil employedcan be materially decreased, as compared to heretofore usedcompositions, and yet provide a compounded composition highly effectivefor use as a lubricant, and particularly for lubrication of marineengines operated under wet conditions, e. g., wick-feed typereciprocating engines. Due to the marked decrease in concentration ofbodied fatty oils that may be used by practicing this invention, and yetobtain desired results, with elimination of objectionable featuresassociated with previously employed compositions,

cating composition by incorporating the two foregoing described hexitolanhydride derivatives into a suitable mineral oil base stock containinga concentration of blown fatty oil insuflicient by itself to modify themineral oil to the extent required for highly satisfactory performancein marine engine lubrication. For example, whereas lubricating oilsheretofore employed essentially contained a substantial concentration ofblow fatty oil, e. g., about by weight, the present invention embodiescompounded mineral oil compositions that are at least equal, and undersome circumstances, actually superior in performance thereto even thoughthe bodied fatty oil content of the novel compositions is markedly lessthan 15%, e. g., as low as 3.0% or even as low as 1.0% by weight, basedon the weight of mineral oil. Compositions prepared in accordance withthis invention and containing 1.0% by weight by blown rapeseed oil haveprovided excellent results under actual test in lubricating of wick-feedreciprocating engines in harbor craft.

In preparing the novel compositions embodied herein, the componentsthereof may be simply blended to provide a solution using heat,agitation and/or other suitable means to expedite solution. In preferredembodiment, the novel compositions are prepared by adding the blownfatty oil and the two component additives to a. suitable mineral oilbase stock, and heating the mixture, such as to about 120 F., withagitation to expedite solution. The additive may be added as acombination of a partial ester of a hexitol anhydride and apolyoxyalkylene derivative of a hexitol anhydride partial ester, orthese components may be individually added, highly satisfactory resultsbeing obtained irrespective of the manner of incorporating thesecomponents into the mineral oil base stock.

As embodied herein, the novel compositions comprise the essential use incombination of a suitable mineral oil base stock, a blown fatty oil, apartial ester of a hexitol anhydride, and a polyoxyalkylene derivativeof hexitol anhydride partial esters. Thus; whereas the use of theforegoing components in combination provide the desired results, I havefound that under certain circumstances, compositions similar theretoexcept that an essential ingredient has not been used do not provide thehighly effective results embodied herein. For example, compositionscontaining a suitable mineral oil base stock, a blown fatty oil and onlyone of the two aforedescribed hexitol anhydride derivatives usuallyprovides a composition inferior in solubility and/or emulsifyingcharacteristics. Similarly, compositions containing a suitable mineraloil base stock and the two component additive, but devoid of a blownfatty oil, are usually inferior in solubility and/or emulsifyingcharacteristics, the inferior-solubility characteristics apparentlybeing due to the absence of blown fatty oil in the composition.

The oil used as the base stock in preparing my novel compositions may bederived from any of l the available crude oils, such as parafliniccrudes,

naphthenic base crudes, mixed base crudes, and fractions or blends ofsuch crudes. The base stock is preferably a mineral oil of high qualityand of desired viscosity, pour point, gravity, etc., for intended usage.Although it is not intended that my invention be limited thereto, assuitable mineral oil stocks derived from various crudes may be employed,I have for purpose of illustration set forth hereinafter asbase stock Aand base stock B examples of base stocks derived from naphthenic crudethat may suitably be employed in practicing this invention:

Base Stock Base Stock A B API Gravity l6. 0 18. 6-22. 0 Pour Point F 150 Viscosity at 210 F. (Saybolt Universal Seconds) 80-90 47-49 Inpreparing my novel compositions, I preferv ably employ blown rapeseedoil as the blown fatty oil, although other blown fatty oils of thesemidrying type may be used. Thus, for example, blown peanut oil, blownmustard seed oil, certain fractions of fish oils, and similar fatty oilsmay be employed. As is known to those skilled in the art, such oils areusually prepared by blowing semi-drying fatty oils with air whereby theoils are polymerized and/or oxidized to form thehighly viscous materialsknown as blown fatty oils.

As stated hereinbefore, the essential components of my novelcompositions that enable use of materially reduced concentrations ofblown fatty oils comprise a suitable mineral oil base stock, a blownfatty oil, a partial ester of a hexitol anhydride, more preferably afatty acid partial ester of hexitol anhydride, and a polyoxyalkylenederivative of hexitol anhydride partial esters. For purposes ofconvenience, the partial esters of hexitol anhydrides are hereinafterreferred to as group A compounds, and the polyoxyalkylene derivatives ofhexitol anhydride partial esters as group B compounds. The hexitoianhydrides, as embodied herein, include the sorbitans and sorbides,mannitans and mannides. In preferred embodiment, the partial esters ofthe hexitol anhydrides are obtained by esterifyihg the hexitolanhydrides with fatty acids containing at least twelve carbon atoms toform the group A compounds. As compared to group A compounds, the group3 compounds are characterized in that the free hydroxyls of the hexitolanhydride partial esters are modified by reaction with alkylene oxidewhereby the group 3 compounds have a higher ratio of ether oxygen tohydrowl; that is, the group B compounds comprise thehydroxypolyoxyethylene ethers of the group A partial esters. Such etherscan be prepared by methods known to those skilled in the art, as forexample, by etherifying the partial ester by heating with a preformedpolyethylene glycol or by reacting the ester with ethylene oxide in thepresence of a suitable catalyst. With reference to the group Acompounds, I prefer to employ the partial esters of sorbitan, includingthe mon'olaurate, monopalmitate, monostearate, trioleate, and the like,esters of sorbitan. With reference to the group 13 compounds, I preferto employ the polyoxyalkylene derivatives of the sorbitan partialesters, as enumerated hereinbefore, the hydroxy polyoxyalkylene ether ofsorbitan monooleate being a highly suitable example thereof.

In order to further describe my invention, several compositions are setforth hereinafter that were prepared and tested in accordance withperformance requirements as described in bureau of Ships N. B. S. 431,Navy Symbol 4.065, relating to lubrication of reciprocating-marineengines of the wick-feed type. Apart from certain requirements relatingto composition, physical characteristics, and the like, thespecification contains a wickteed test and an emulsion test that must bemet by a composition considered satisfactory under the specification.The wick-feed test is set forth as method 200.1 in Federal SpecificationW-L-lill-C and performance thereunder indi cates the wick-feedingcharacteristics of the oil under test by measuring the flow of oil bywicking action over prescribed time intervals. In order for a marineengine oil-of the type falling within the specifications to meet thewick-feed test, the oil composition should retain 30% flow at the end of14 days under the conditions of the test procedure. With reference tothe emulsion test under the specification, a given amount ofthe testcomposition is mixed with an equal volume of distilled or salt water (1%NaCl) at 130 F. to form an emulsion, and the emulsion thus formedallowed to stand for minutes. In order to satisfactorily pass the test,the oil should remain emulsified for the 00-minute period.

. Percentageby Weight Composi- Composi- Composition 1 tion 2 tion 3 BaseStock A 58. 0 50.0 50. 0 Base Stock 13 32.0 47. 0 47. 7 Blown RapeseedOil 10. 0 3.0 2.0 Sorbitan Trioleata. 0. l Hydroxy Polyoxyalkylene etherof Sorbltan Monocleate 1 0. 15

1 An oily liquid at 0., having a viscosity of 400-600 cp. at 25 0.. anda specific gravity of 1.00 to 1.05.

The foregoing compositions, on being subjected to the aforedescribedemulsion test, gave the following results: both composition 1 containing10 by weight of blown rapeseed oil and composition 2 containing 3% ofthe blown-oil, but devoid of the hexitol anhydride derivatives, failedto pass the emulsion test in that oil separation had occurred beforeconclusion of the 60-minute test period. However, composition 3containing only 2% of blownrapeseed oil and a minor amount of which didnot contain the afo'redescribed two derivatives of sorbitan. Moreover,the emulsion formed by composition 3 was more dense than that of theother two compositions, indicating that more complete water dispersionoccurred in composition 3 which is a desired characteristic forlubricating compositions of this type; addi tionally, the emulsion ofcomposition 3 indicated superior adhesiveness to metal surfaces underlubrication.

In view of the results of the foregoing tests, it is clearly evidentthat use of a minor amount of the two component additive enables theproduction of highly suitable lubricating oils without necessity ofemploying the substantially large proportional amounts of blown fattyoils heretofore found essential for suitable performance em= bodied bythe requirements of specification, Navy Symbol 4065. For example,whereas mineral oils 7 containing 10% by weight of blown rapeseed oildid not pass the specification requirements, a composition (No. 3)containing only 2% of the blown oil and minor amounts of the two hexitolanhydride derivatives satisfactorily passed the specificationrequirements as to performance, the superior performance being due tothe presence of only 0.3% by weight as the sum of the hexitol anhydridederivatives. Not only does the present invention provide for a materialreduction in the concentration of blown fatty oil that may be employedin the lubricating compositions, but additionally, advantages accrue tosuch compositions in that the amount therein of objectionable free fattyacids normally present in blown fatty oils is correspondingly reduced.For example, blown rapeseed oils usually contain about 0 to 7% of freefatty acids, and in some cases up to about 9%, whereupon compoundedmineral oils containing about 15% of bodied rapeseed oil contain about1% of free fatty acids. However, by em ploying the present invention,satisfactory compositions are prepared that need not contain more than 2or 3%, or even not more than about 1% of the blown oil, in which casethe free fatty acid concentration of the compounded oil is reduced to anegligible amount.

Example If Additional compositions, as embodied herein, were preparedemploying proportional amounts of ingredients as set forth below, andsubjected to the tests employed with the compositions of Example I. Ineach case, the compositions performed satisfactorily in a manner similarto composition 3 in Example I.

each of the two sorbitan derivatives passed the test in that no oilseparation occurred before termination of the test period.

The foregoing compositions were also subjected to the wick-feed test asaforedescribed and the performance of composition 3 thereunder was 76oleate; similar compositions except that only one 0! these sorbitanderivatives is employed, or when the composition contains both sorbitanderivatives but is devoid of blown rapeseed oil, exhibit inferiorperformance either in solubility characteristics, emulsifying capacity,or both. Thus, a mineral oil base containing 3% of blown rapeseed oiland 0.5% of either sorbitan trioleate or the polyoxyalkylene derivativeof sorbitan monooleate usually exhibits inferior emulsifying orsolubility characteristics; furthermore, a base mineral oil stockcontaining 0.5% o! sorbitan trioleate and 0.5% of the polyoxyalkylenederivative of sorbitan monooleate, but devoid of bodied rapeseed oilgenerally exhibits unsatisfactory solubility characteristics.Accordingly, as stated hereinbefore, the improved lubricatingcompositions as embodied herein are obtained by using in combination theMore-described ingredients comprising a suitable mineral oil base stock,a bodied fatty oil, 8. fatty acid partial ester of a hexitol anhydride,and a polyoxyalkylene derivative of hexitoi anhydride partial fattyesters.

Although in the foregoing examples certain concentrations have been setforth for the cornbination oi ingredients employed in preparing my novelcompositions, such concentrations have been set forth for illustrativepurposes, and are not to be considered limitative. As will beappreciated by those skilled in the art, the concen trations ofingredients may be varied depending on factors such as solubilitycharacteristics, the conditions under which the compounded composi tionis to be used, the type and composition or specific ingredientsemployed, and the like. In general, however, compounded compositions asembodied herein usually comprise a major proportional amount 02 asuitable mineral oil base stock containing up to about 15% of a blownfatty oil, and minor, but effective, amounts of each or. the hexitolanhyclricie derivatives as described hereinbefore. In a preferredembodiment, particularly for lubricating of reciprocating marineengines, the compounded composition comprises at least about 85% byweight of a suitable mineral oil base, up to about 1.0% of each of thetwo types of hexitol anhyclride derivatives, and the balance a blownfatty oil. Although the amount of each or these derivatives may exceedabout 1.0% by weight of the compounded composition without apparentdeleterious efiects, such higher amounts are not usually necessary, asfrom about 0.05 to about 1.0% of each derivative has been found toprovide highly satisfactory results. Furthermore, although the twohexitol anhydride derivatives may be employed in other than substantially equal amounts by weight, as long as an efiective amount ofeach derivative is employed, it is preferred that these derivatives beused in substantlally equal amounts by weight as usage in this mannerprovides more efiective results in performance, solubility, emulsifyingcharacteristics, and the like. A particularly suitable ex ample of acomposition falling within the foregoing preferred ranges of ingredientconcentrations is illustrated by the composition hereinbefore designatedas composition 3, containing about 97% of mineral oil, about 0.15% ofsorbitan trloleate, about 0.15% of the hydroxy-polyoxyalkylene ether ofsorbitan monooleate, and the balance substantially all blown rapeseedoil.

Although the present invention has been described in conjunction withcertain preferred embodiments thereof, those skilled in the art willreadily recognize that variations and modifications can be made. Suchvariations and modifications are to be considered to be within thepurview of th specification and the scope of the appended claims.

I claim:

. i. A lubricating composition suitable for use under aqueous conditionsand characterized by forming upon admixture with water a water-inoilemulsion having lubricating properties which comprises a mineral oil inmajor proportional amount having dissolved therein (a) at least about 1%but less than about 15% by weight of a blown semi-drying fatty oil and(b) about 0.05 to about 1.0% by weight of (1) a hexitol anhydridepartially esterifled with a fatty acid of at least 12 carbon atoms and(2) about 0.05 to about 1.0% by weight of a polyoxyaliwlene derivativeof a hexitol anhydride partially esterified with a fatty acid of atleast 12 carbon atoms.

2. A composition, as defined in claim 1, where in the partial ester of ahexitol anhydride is sorbitan partially esterified with a fatty acid oiat least 12 carbon atoms.

3. A composition, as defined in claim 1, wherein the polyoxyalkylenederivative is a hydroxypolyoxyalkylene ether of a sorbitan partiallyesterified with a fatty acid of at least 12 carbon atoms.

e. A composition suitable for lubrication of marine engines under wetconditions and charnotarized by forming a water in-oil emulsion uponadmixture with water comprising a mineral oil of lubricating grade inmajor proportional amount having dissolved therein; about i to 15% byweight of blown rapeseed oil, about 0.05 to 1.0% by weight of a hexitolanhydride partially esterified with a fatty acid of at least 12 carbonatoms and about 9.05 to 1.0% of a hydroxy-poly oxyalkylene ether of ahexitol anhydride partially esteriiiecl with a fatty acid or at least 12carbon atoms.

5. A composition comprising a. mineral oil base stock in majorproportional amount having dissolved therein about i. to 15% by weightof blown rapeseed oil, about [Hi5 to 1.0% of a sor bitan partiallyesterified with a fatty acid of at least 12 carbon atoms and about 0.05to 1% of a hydroxy-polyoxyallrylene ether of a sorbitan partiallyesterified with a fatty acid of at least 12 carbon atoms.

6. A composition comprising a mineral oil in major proportional amounthaving dissolved therein about 1 to 15% by weight of blown rapeseed oil,about 0.05 to 1.0% or sorbitan trioleate and 0.05 to 1.0% of apolyoxyalkylene ether or sorbitan monooleate.

7. A composition comprising a mineral oil in major proportional amounthaving dissolved therein about 1.0 to 3.0% by weight of blown rapeseedoil, about 0.15% of sorbitan trioleate and about 0.15% of ahydroxy-polyoxyalkylene ether of sorbitan monooleate.

ST P. WAUGE.

REFERENCES @HCEIZZJ The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 2,231,167 Lazar Feb. 11, 19412,228,429 Wright Jan. 14, 194:1 2,398,193 Sharp Apr. 9, 1940 o'rnnaREFERENCES "Atlas spans and Atlas Tweens." publication of Atlas Powder00., publication date about November, 10%2.

